The present embodiments relate to dynamically adapting a software-defined network.
In large software-defined networks (SDN networks) with massively distributed network nodes and end devices, the scalability of the SDN controller may be difficult. The performance and stability of a single SDN controller may be affected due to the large SDN network.
In addition to scalability issues, fault-tolerance of the control plane is an important requirement for applying SDN in practice in industrial applications. In single-controller deployments, the SDN controller is a single point of failure (SPOF) in the control network. Since no system may be assumed to be 100% available, backup controllers are to be deployed to offset the SPOF property.
Multiple approaches present Control Plane (CP) slicing, where network users (e.g., tenants) are offered a slice of physical resources (CP multi-tenancy) and, in addition, are provided a way to orchestrate the resources as per corresponding application needs. Therefore, there is a need for a concept that facilitates SDN controllers per network resource slice and paves the way for on-demand network services.
Fluid Replication (Noble, B., Fleis, B., Kim, M., (1999), A Case for Fluid Replication) is a service replication strategy that detects changes in demand for services and resources and automatically replicates services when and where necessary. By fluid replication, servers that host the service necessary to serve a client's request are dynamically deployed closer to the user (e.g., client of the service), hence enabling access to service with lower overall delay experienced by a user. These replicas are placed on WayStations—service nodes in the infrastructure that provide replication services.
Civanlar, S., Lokman, E., Kaytaz, B., & Tekalp, A. M. (2015), Distributed management of service-enabled flow-paths across multiple SDN domains, 2015 European Conference on Networks and Communications, EuCNC 2015, 360-364, http://doi.org/10.1109/EuCNC.2015.7194099, proposes that each SDN controller shares with other SDN controllers a summarized view of a corresponding network graph, which is essentially an equivalent virtual network between corresponding gateway forwarders, and the associated service capabilities.
Basta, A., Blenk, A., Lai, Y. T., & Kellerer, W. (2015), HyperFlex: Demonstrating control plane isolation for virtual software-defined networks, Proceedings of the 2015 IFIP/IEEE International Symposium on Integrated Network Management, IM 2015, 1163-1164, http://doi.org/10.1109/INM.2015.7140460, introduces the concept of an SDN hypervisor to support the multi-tenancy requirements in the SDN Control plane. A set of physical resources are assigned to different network tenants, and the tenants are allowed the access to a corresponding assigned share by making reservation requests at a logical instance of an Network Controller.
The international patent application WO 2015/096758 A1 discloses a network having a hierarchical SDN architecture, where the network is sub-divided into multiple regions, and each region is assigned to a different SDN controller for collecting network status information to be fed to a root SDN controller. The SDN controller computes costbased parameters for distribution to regional SDN controllers for locally adapting resources.